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28 .\" @(#)kdump.1 8.1 (Berkeley) 6/6/93
35 .Nd display kernel trace data
46 command displays the kernel trace files produced with
48 in human readable format.
51 in the current directory is displayed.
53 The options are as follows:
56 Display the ABI of the traced process.
58 Display the CPU number with each trace entry.
60 Display all numbers in decimal.
62 Display elapsed timestamps (time since beginning of trace).
64 Display the specified file instead of
67 List the thread ID (tid) of the thread with each trace record, if available.
68 If no thread ID is available, 0 will be printed.
70 Loop reading the trace file, once the end-of-file is reached, waiting for
78 Suppress ad hoc translations.
81 tries to decode many system calls into a more human readable format.
84 values are replaced with the macro name and
86 values are replaced with the
89 Suppressing this feature yields a more consistent output format and is
90 easily amenable to further processing.
92 Display only trace events that correspond to the process or thread
94 This may be useful when there are multiple processes or threads recorded in the
97 Display relative timestamps (time since previous entry).
99 When decoding STRU records, display structure members such as UIDs,
100 GIDs, dates etc. symbolically instead of numerically.
102 Display system call numbers.
104 Suppress display of I/O data.
106 Display absolute timestamps for each entry (seconds since epoch).
116 is line oriented with several fields.
117 The example below shows a section of a kdump generated by the following
119 .Bd -literal -offset indent
120 ?> ktrace echo "ktrace"
124 85045 echo CALL writev(0x1,0x804b030,0x2)
125 85045 echo GIO fd 1 wrote 7 bytes
128 85045 echo RET writev 7
131 The first field is the PID of the process being traced.
132 The second field is the name of the program being traced.
133 The third field is the operation that the kernel performed
134 on behalf of the process.
135 If thread IDs are being printed, then an additional thread ID column will be
136 added to the output between the PID field and program name field.
138 In the first line above, the kernel executes the
140 system call on behalf of the process so this is a
143 The fourth field shows the system call that was executed,
144 including its arguments.
147 system call takes a file descriptor, in this case 1, or standard
148 output, then a pointer to the iovector to write, and the number of
149 iovectors that are to be written.
150 In the second line we see the operation was
152 for general I/O, and that file descriptor 1 had
153 seven bytes written to it.
154 This is followed by the seven bytes that were written, the string
156 with a carriage return and line feed.
159 operation, showing a return from the kernel, what system call we are
160 returning from, and the return value that the process received.
161 Seven bytes were written by the
163 system call, so 7 is the return value.
165 The possible operations are:
166 .Bl -column -offset indent ".Li CALL" ".No data from user process"
167 .It Sy Name Ta Sy Operation Ta Sy Fourth field
168 .It Li CALL Ta enter syscall Ta syscall name and arguments
169 .It Li RET Ta return from syscall Ta syscall name and return value
170 .It Li NAMI Ta file name lookup Ta path to file
171 .It Li GIO Ta general I/O Ta fd, read/write, number of bytes
172 .It Li PSIG Ta signal Ta signal name, handler, mask, code
173 .It Li CSW Ta context switch Ta stop/resume user/kernel wmesg
174 .It Li USER Ta data from user process Ta the data
175 .It Li STRU Ta various syscalls Ta structure
176 .It Li SCTL Ta Xr sysctl 3 requests Ta MIB name
177 .It Li PFLT Ta enter page fault Ta fault address and type
178 .It Li PRET Ta return from page fault Ta fault result